Using rubber bands brings some pro's to the 'situation'
Cons are that they have to be used for some length depending on the
elasticity factor.
Improvements from a 'solid' connection to an elastic one are many .
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It wasn't my intent to insult your guru.
What I found interesting was that here was another piece of evidence, another person who did the experiment and another person who reported their results. That they found such a large impact from the box shape, was for me, a useful piece of information. I thought others may find it interesting. Each to their own.
As for Romy's site - it contains a lot of discussion covering a lot of topics. I don't think you really believe you are expert enough on all those topics to claim that the discussion is all utter rubbish. For me, I've found a lot of interesting discussion on that site regardless of whether I agree with the opinions it contains. I don't agree with your sweeping statement at all.
An enclosure does more than "two things." Hopefully we're not seeking the ONE true path to an illusionary result. Personally I find the 2 Daves to be illuminating in their different views. I lean toward PlanDave's approach because I want clarity and minimal filtering which I, a dummy, don't comprehend. Nevertheless, Dave S has done the work. That doesn't make Dave D's approach "unfounded" at all. If you must choose one, was it your mother and her line, or your father and his? Remember, only ONE.
Are the Sharks so much better different other than the Jets?
Are the Sharks so much better different other than the Jets?
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You haven't insulted anyone, Bigun. It's just that there is tons of stuff on the internet. How do you know what's useful and what's not? Someone did a test and concluded, "yes, this one sounds good. This other one, not so much." And we are to take something from that?
I would rather spend my time on something that has been proven to work. Planet10 would also know a thing or two about cabinets, and Speaker Dave certainly does. And if they are showing the way forward, why bother with such stuff?
Besides, what good is that piece of information anyway? Was your next project a deep box? And now you are thinking about it? How deep does it have to be, or how shallow before a change is heard? Was the backwave properly absorbed in the experiment?
If you reason based on the info that's been provided in this very thread, there shouldn't be any audible difference between two box shapes. Unless we are missing something and then, the two Dave's can tell us what we are missing.
I would rather spend my time on something that has been proven to work. Planet10 would also know a thing or two about cabinets, and Speaker Dave certainly does. And if they are showing the way forward, why bother with such stuff?
Besides, what good is that piece of information anyway? Was your next project a deep box? And now you are thinking about it? How deep does it have to be, or how shallow before a change is heard? Was the backwave properly absorbed in the experiment?
If you reason based on the info that's been provided in this very thread, there shouldn't be any audible difference between two box shapes. Unless we are missing something and then, the two Dave's can tell us what we are missing.
One way to implement massive boost is to run an additional pre-amp section prior to to the bass amplifier section so that for a given signal level it runs with much more gain, e.g. +10dB, +20db or +30dB relative to the mid-range and hf amps.
This approach can be nearly mandatory if we use digital eq for the OB bass section. ... most DAC output sections are limited to small output voltages, and the extreme eq would push them beyond their limits very quickly. So in most cases, better to have excess analog gain and throw some of it away than to try and boost digitally.
Hi Jack, isn't that what Behringer do with their analogue crossovers, while I seldom use it there is a boost/cut on each separate circuit although it is only +/- 6dB i don't think any of my speakers would handle +30dB of bass boost at 30hz ( pre-amp has parametric +/- 12dB tho) so is that +18dB if I crank the boost all the way up??
Either way i would have to leave the room on any volume over 6 on the dial
Either way i would have to leave the room on any volume over 6 on the dial
I haven't worked w. Behringer's analogue units, only their digital ones.
And on their DEQ2496 or DCX2496, due to sound quality, I mod them to bypass the output sections in favor of going direct out from the DAC via transformers or coupling caps. So any additional built-in analog boost becomes unavailable with the mods.
The thing about digital EQ is that if signal peaks are near the "0dB" full excursion limit, boosting that by say +6dB will result in massive distortion, really horrible. + 18dB? Yeesh, I shudder to think about it....
So, if we want +18dB boost, best to get +20dB from the pre-amp/amp combo or use an amp with extremely high input sensitivity and gain and then use the digital eq only to cut, not boost... the result is more head-room in the digital section, and that's a good thing.
The trouble with the above approach is that high sensitivity amps are rare, thus the need for an in-line boost pre-amp or trafo. More complexity and cost, especially for a high-quality in-line section. Even so, I'd rather use digital eq where possible.
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To be honest I'm not sure how to describe my Yamaha pre-amp except to say it is starting to show its age, but when new maximum output was supposed to be 8.6 volts.
Would that qualify? I think that is over the usual input for any of my power amps
Would that qualify? I think that is over the usual input for any of my power amps
Even if it's an old pre-amp, if it is functional it can probably still put out the rated voltage.
And while it's true that 8.6V may be more than some amps can handle, in reality you're only likely to hit that kind of peak level on rare occasion, unless you like to abuse your ears and speakers.
So (assuming the amps are all equally sensitive) with the deq, starting with no eq at all, if you were to crank the level up to where each section is putting out 1V...... You would then feed the bass output into your pre and adjust the volume control on the pre so it is putting out 8V , then that 8X voltage ratio gives you about +18dB of broad-band bass boost prior to eq. So then, instead of boosting the bass in the eq, you would create a low-pass filter with the eq and crossover to reduce the mid-bass by the correct amount.
And voila, bass boost without overdriving the DACs! The speakers will still be seeing the same power and EQ, it's just that this way your digital eq isn't going to overdrive the dac section.
I used cotton, not rubber, maybe self damping in the vertical, but free moving horizontally. I don't know what effect different lengths would have.
BTW, I wish my Italian was as good as your English!
I once made 2 identical boxes, except for material, MDF or 700gm chipboard. Clear difference in sound. Also front baffle rigidity would change with different height and width? Hard to separate the various effects? I have no technical expertise, only empirical/observational.
unfortunately this does not work for OB, where you need +20db or so only below 60-40hz. If you apply gain through a preamp, you end up with +20db or whatever value at 80-100hz too, and you may not want that especially if you run the woofers high like Stig Erik does! you end up shifting the filter slopes completely, a +1/-1db pot is great to tweak the response to perfection, but certainly not such a big gain.. Life would be so easy otherwise! I did try the DCX2496 in the past, massive digital clipping when used like that, I just did not manage to get any result without huge sensitivity loss..
I don't have much experience with enclosures, but SL released the Thor closed box woofer after the Orions to add deep infra bass, it is not getting much attention and most of people who built it are not using it, they report way too much difference in the "openess" of the sound, but this could well be a polar issue and nothing else... On the other hand, people lucky enough to have a true IB at home report similar sound to an OB.. Not much science here I know, but there does seem to be a subjective issue with the volume..
One has to wonder as well, why punish a woofer in such an aweful way enclosing it on a tiny box and inflincting tons of watts to make it move??? Free that boy! 😉
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I have an Audio Nirvana Super 15" driver and I want to build a box for it. The drawings I got with the driver are for a big box, at least it's big compared with anything I've built before, and big enough that my wife will notice it this time 😉
It will stand 4' high, with 2' wide baffle and also 2' deep - so it neatly uses the full size 2' x 4' sized Birch plywood sheets available from my local store. Of course that's not exactly golden ratio territory but it gives me something with enough volume to accommodate around 100 units of my last speaker !!! (Martello).
I figure this counts as a reasonably deep box. I will build it so that the back is screwed on and can be easily removed, that way I can listen to it 'open back' too. Makes it into a giant U-frame.
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You'll change the nature of the common part of the cabinet when attaching that way. Support the rear panel and have it touching the cabinet lightly via some soft weatherstripping and you should isolate the backwave, the rear panel itself and lower frequency pressure effects when comparing.Bigun said:
Wouldn't the panel excursion overload recovery time increase? The seemingly arbitrary instantaneous displacement could be an issue with some bracing schemes. This seems to suggest that enough is enough.
24" is pretty deep for a "U" frame Bigun. Frames that deep produce a response similar to having distributed bass not being time aligned with the mains. Definition seems to improve as the cavity depth decreases.
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any ideas on how it should be 'supported' ?
I agree, it's a bit of an extreme example of a U-frame. It's not really a U-frame is it. It's really an open back box. That's OK, it's an experiment. My primary aim is to make a box.
why punish a woofer
Isn't that the problem with OB; that excursion requirements = dollars that some of us don't have to spend for modern big xmax drivers. Besides, we have our loyalties, right? TL vs BR vs AS vs BLH etc...now no box at all? Some of us have decades invested here! Don't force me to learn!
Isn't that the problem with OB; that excursion requirements = dollars that some of us don't have to spend for modern big xmax drivers. Besides, we have our loyalties, right? TL vs BR vs AS vs BLH etc...now no box at all? Some of us have decades invested here! Don't force me to learn!
I'd assume that panel resonances on the rear panel itself are not the point of the excercise, so holding the panel flat and removing output from the rear of it ought to help.
Without mechanical coupling, without significant rear panel resonances and with the right amount of internal absorption, the only difference should be with air coupled breathing modes and the driver resonance, and the contribution of the dipole itself.
Support the back panel with hardwood battens around the edges, 42*19mm or
2 *1inch on edge. set in by the thickness of the back panel. use "T" nuts and as mentioned foam weather strip for the airtight seal
2 *1inch on edge. set in by the thickness of the back panel. use "T" nuts and as mentioned foam weather strip for the airtight seal
I am not and actually, I am with you here, I dont have these $$$$ either to be honest! As the topic is about box coloration, I was just making a comment about IB.. 🙂
Stig Erik, what happens with bass localization when you cross it so high? I thought the upper limit for physical separation was in the 100hz range?